1. Field of the Invention
The present invention relates to a plasma lighting system, and more particularly, to an eco-friendly cooling apparatus of a plasma lighting system which can prevent components therein from being damaged by shielding foreign substances at the time of installing the plasma lighting system outdoors, and prevent noise at the time of installing it indoors.
2. Description of the Related Art
Generally, a plasma lighting system provides high economical efficiency and an idealistic natural light than any other conventional lamps.
A light emitting principle of the plasma lighting system will be explained. First, microwave (high frequency) generated from a magnetron of a high frequency oscillator makes inert gas in a bulb into plasma, which is ionized status.
The above plasma status is maintained to make metal compound in the bulb emit light continuously, thereby proving high quantity of light without an electrode.
The plasma lighting system has following advantages.
Luminous flux corresponding to that of four metal halide lighting system of 400 W can be generated by one plasma lighting system, energy consumption can be reduced by 20% or more, and an additional stabilizer is not needed since a built-in stabilizer is used.
Also, since light is emitted by the light emitting principle of the plasma without a filament, the apparatus can be used for a long time without lowering the flux.
Also, since continuous optical spectrum same as the natural white-light is realized, the plasma lighting system functions similarly to the sun light. The plasma lighting system is useful where the sun light is not streamed into or where color discrimination is made.
The apparatus does not use fluorescent material to protect visual acuity, and is able to minimize radiation of ultraviolet ray and infrared ray to provide comfortable and eco-friendly lighting environment.
Hereinafter, constructions of the conventional plasma lighting system will be explained.
FIG. 1 is a longitudinal cross-sectional view showing an entire construction of a plasma lighting system in accordance with the conventional art.
As shown in FIG. 1, the conventional plasma lighting system comprises: a magnetron 20 installed at and upper end of one side of a casing 10 for generating electromagnetic wave; a power supply 30 installed at an upper end of another side of the casing 10 with an opposite state to the magnetron 20 for supplying AC power to the magnetron 20 by boosting into a high voltage; a wave guide 40 connected to an outlet of the magnetron 20 and installed between the magnetron 20 and the power supply 30 for transmitting the electromagnetic wave generated from the magnetron 20 to a bulb; a bulb 50 connected to a middle upper portion of the wave guide 40 and provided with light emitting material, buffer gas, and discharge catalyst material therein for generating light by making the filled fluorescent material into plasma by the electromagnetic wave energy; a resonator 60 including the bulb 50 and passing light generated from the bulb 50 while blocking the electromagnetic wave transmitted from the wave guide 40; reflectors 70 attached to a middle upper portion of the casing 10 for containing the resonator and thus intensively reflecting the light generated from the bulb 50; a dielectric mirror 80 attached to rear both sides of the bulb 50 and to an inner side of the resonator 60 for passing electromagnetic wave and reflecting light; and a cooling fan assembly 90 installed at a lower side of the casing 10 for cooling the magnetron 20 and the power supply 30.
The casing 10 is divided into an upper case 11 and a lower case 12. An electromagnetic wave passing hole 11a for inducing electromagnetic wave by connecting the wave guide 40 and the resonator 60 is formed at a center of the upper case 11, and air exhaustion holes 11b for exhausting air sucked into the casing 10 from outside to the outside by the cooling fan assembly 90 which will be later explained are formed at right and left sides of the electromagnetic wave passing hole 11a. 
Also, an air suction hole 12a is formed at a middle lower portion of the lower case 12, and air suction passages 12b separated right and left by being connected to the air suction hole 12a are formed. A fan 92 which will be later explained is installed at a center of the air suction passages 12b. 
In the meantime, the magnetron 20 and the power supply 30 are located between the air suction passages 12b and the air exhaustion holes 11b so as to correspond to both outlets of the air suction passages 12b, and thus fixed to both sides of the wave guide 40, respectively.
The wave guide 40 is formed as a ring type, and a magnetron insertion hole 41 is formed to be connected to the magnetron 20 at a peripheral wall of one side, and an electromagnetic wave guide hole 42 having a closed lower end and an opened upper end is formed to be connected to the electromagnetic wave passing hole 11a of the upper case 11.
The bulb 50 is composed of a light emitting portion 51 formed as a sphere shape by using quartz, a light transmitting substance, so that buffer gas, light emitting material, and discharge catalyst material can be filled therein; and a shaft portion 52 integrally formed at a center of a lower side of the light emitting portion 51 and engaged to a rotation shaft of a bulb motor M.
Also, the cooling fan assembly 90 is composed of a fan motor 91 fixed to a center of the casing 10; and a blower 92 engaged to a rotation shaft of the fan motor 91 to be rotated together and installed at the air suction passage 12b of the lower case 12 for sucking air outside of the casing 10 into the casing.
Operations of the conventional plasma lighting system are as follows.
First, if a driving signal is inputted to the power supply 30 by a controlling unit, the power supply 30 boosts AC power and then supplies the boosted high voltage to the magnetron 20. The magnetron 20 is oscillated by the high voltage and generates electromagnetic wave having high frequency. The generated electromagnetic wave is emitted into the oscillator 60 through the wave guide 40 and discharges the material in the bulb 50, thereby generating light having a peculiar emitting spectrum. The light is reflected forward by the reflector 70 and the dielectric mirror 80, thereby lightening a space.
At this time, heat of high temperature is generated from the magnetron 20 and the power supply 30. Especially, in the magnetron 20, some high frequency energy which is not emitted among the high frequency energy generated by heat electron disappears by heat, thereby enhancing inner temperature of the casing 10. According to this, the fan 92 is operated, and as shown in FIG. 1, cool air of outside is sucked into the casing 10 to cool heat generated from the magnetron 20.
However, in the conventional lighting system, an inner part of the casing is formed as a single space, thereby having a difficulty in emitting heat. Also, heat of high temperature generated from the magnetron is transmitted to the power supply to destroy inner components thereof, thereby degrading efficiency and life span of the plasma lighting system.
Also, in the conventional plasma lighting system, air-cooling using the fan is used in order to cool heat generated from the magnetron. In this case, rain water or foreign substance is introduced into an air inlet and an outlet at the time of installing the plasma lighting system outdoors to damage the inner components, and at the time of installing it at the interior, noise generated from the fan caused inconvenience.